Rule 7: Avoid CSS Expressions7(Chapter 7 of High performance Web Sites)
The problem with expressions is that they are evaluated more frequently than most
people expect.Not only are they evaluated whenever the page is rendered and
resized, but also when the page is scrolled and even when the user moves the mouse
over the page.Adding a counter to the CSS expression allows us to keep track of
when and how often a CSS expression is evaluated.
Workarounds: Event handlers.
people expect.Not only are they evaluated whenever the page is rendered and
resized, but also when the page is scrolled and even when the user moves the mouse
over the page.Adding a counter to the CSS expression allows us to keep track of
when and how often a CSS expression is evaluated.
Workarounds: Event handlers.
